(English Medium) ICSE Class 10 - CISCE Important Questions

Name the metallic ions that should be present in the electrolyte when an article made of copper is to be electroplated with silver.

Give reasons why In the electroplating of an article with silver, the electrolyte sodium argentocyanide solution is preferred over silver nitrate solution.

State one relevant observation for the following:

At the anode when aqueous copper sulphate solution is electrolysed using copper electrodes.

Copy and complete the following table:

Choose the correct answer from the options given below:

The electrolyte used for electroplating an article with silver is

A. Silver nitrate solution

B. Silver cyanide solution

C. Sodium argentocyanide solution

D. Nickel sulfate solution

Give one word or phrase for the following:

Electrolytic deposition of a superior metal on a baser metal.

Arrange the following according to the instruction given in bracket:

Cu²⁺, Na⁺, Zn²⁺, Ag⁺ (The order of Preferential discharge at the cathode)

Electroplating steel objects with silver involves a three-step process.

Step 1: A coating of copper is applied to the object.

Step 2: A coating of nickel is applied to the object.

Step 3: The coating of silver is applied to the object.

1. 1. A diagram of the apparatus used for step 1 is shown
      
      
      1. The chemical process taking place on the surface of the object is \[\ce{Cu^2+(aq) + 2e- ->Cu(s)}\]
         What is the observation seen on the surface of the object?
      2. Explain why the concentration of copper ions in the electrolyte remains constant throughout step 1.
2. Give two changes which would be needed in order to coat nickel on to the object in step 2.
3. Write down the reaction taking place at the positive electrode during step 3.

Give a reason for Alkali metals are good reducing agents.

Name an alloy of lead and tin.

 Match the alloys given in column I to the uses given in column II : 

X [2, 8, 7] and Y [2, 8, 2] are two elements. Using this information, complete the following:

______ is the metallic element.

X [2, 8, 7] and Y [2, 8, 2] are two elements. Using this information, complete the following:

Metal atoms tend to have a maximum of ______ electrons in the outermost shell.

X [2, 8, 7] and Y [2, 8, 2] are two elements. Using this information, complete the following:

______ is the reducing agent.

Name the following:

A metal oxide that can be reduced by hydrogen.

Complete the following by selecting the correct option from the choices given:

The metal whose oxide, which is amphoteric, is reduced to metal by carbon reduction ____________. (Fe/Mg/Pb/Al)

Name the compound added to pure alumina to lower the fusion temperature during the electrolytic reduction of alumina.

Give appropriate scientific reasons for Zinc oxide can be reduced to zinc metal by using
carbon, but aluminium oxide cannot be reduced by a reducing agent

An element L consists of molecules.

When L is heated with iron metal, it forms a compound FeL. What chemical term would you use to describe the change undergone by L?

Write a balanced chemical equation for each of the following reactions :
(i) Reduction of copper (II) oxide by hydrogen